Polymer blending is of great commercial interest because it affords a low cost method of producing new materials. By blending materials with distinctly different properties, one has the potential of producing new materials exhibiting a combination of its component properties. Moreover, blending is usually done in relatively low cost polymer processing equipment. This is in opposition to the high costs associated with developing new materials based on new chemistries and polymerization processes.
Unfortunately most polymers are neither miscible nor compatible, and thus, simply blending polymers together often leads to materials with poor physical properties. Blending incompatible polymers results in materials with grossly course morphologies due to poor interfacial adhesion between its phases. This incompatibility is manifested in poor material properties, such as low strength, low modulus and delamination.
To resolve compatibility issues in polymer blends additional components (compatibilizers) are often added to the blends which act as interfacial agents between the phases. The most common class of polymer compatibilizers is the A-B type block copolymer where each component of the block is chemically identical to one of the two polymers comprising the polymer blend.
This invention describes a means of compatibilizing polyketone polymers with polyolefin polymers, using a method other than the A-B block copolymer described above. Well known in the art, polyketone polymers have excellent mechanical properties and fluid resistance and for this reason enjoy much commercial interest. Polyolefins have poorer fluid resistance than polyketones, yet are ubiquitous and very inexpensive. Therefore, it is natural that there is considerable interest in blending these two materials.
Simple uncompatibilized blends of polyketone polymers and polyolefin polymers, or polyketone polymers and chemically modified polyolefin polymers, are known in the art. Lutz in U.S. Pat. No. 4,816,514 describes obtaining improved processability by melt blending small amounts of polyolefin polymers with polyketone polymers. Likewise, Gergen et al. in U.S. Pat. No. H917 found improved processability from blends of polyketone polymers with maleated polyolefin polymers. Some improvements in properties, particularly barrier properties, are seen by the addition of amorphous olefinic copolymers, preferably those maleated, to polyketone polymers as described by George in U.S. Pat. No. H1,404. Bonner in U.S. Pat. No. 5,859,129 also found good barrier properties in blends of polyketone polymers with the polyolefin polymer: high-density polyethylene (HDPE), optionally grafted with at least one polymerisable ethylenically unsaturated carboxylic acid or derivative thereof. Bonner and Powell (U.S. Pat. No. 5,859,138) also found good barrier properties with blends of polyketone polymer and the polyolefin polymer: linear low-density polyethlene (LLDPE). George in U.S. Pat. No. H1, 375 recognized the problems of blending incompatible polymers such as polyketone polymers and polyolefin polymers. He was able to attain a desirable stiffness by blending cracked polyolefin polymers with polyketone polymers, discovering that by resorting to blends of cracked polyolefin polymers, he could make materials without phase separation.
A compatibilized blend system of a polyketone polymer and an aminated polyolefin polymer which chemically links to the polyketone polymer is described by Weinkauf in U.S. Pat. No. 5,369,170. The scope of Weinkauf's invention is to react diames with maleated polyolefin polymers to produce aminated (amine functional) polyolefin polymers which in turn can chemically graft to polyketone polymers, producing polylefin--polyketone graft copolymers.